Image registration on edible substrates

ABSTRACT

A method of making edible substrates that have an image registered on them in a consistent manner. The method comprises the steps of providing an edible substrate sheet, and an image source, wherein the image source has at least one image. Further, a trigger pulse signal is provided, which relays the frequency of a process element that is communicated to an image disposal device. The image disposal device uses the trigger pulse signal to determine when to dispose an image from the image source. Then an image is disposed on the edible substrate sheet with the image disposal device to form an image-disposed edible substrate sheet. And then a portion of the edible substrate sheet that comprises an image is separated into an individual piece.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to U.S. ProvisionalApplication Ser. No. 60/669,094, filed Apr. 7, 2005, which is hereinincorporated by reference.

FIELD OF INVENTION

The present invention relates to edible substrates having an imagedisposed thereon, particularly to edible substrates wherein said imageis in proper registration.

BACKGROUND OF THE INVENTION

Foods provide more than just physical sustenance. Food also providesenjoyment through means such as visual appeal. Many popular food items,such as cookies, cakes, and candies, comprise some sort of decorationthat makes the food item more visually appealing. Printing on edibleitems such as snacks can provide an added level of excitement beyond thesnacking itself. The printed content can be in the form of graphics,text or combinations, and it can be used to deliver, for example, games,stories, jokes, and educational facts. This new level of excitement maybe, however, jeopardized by a printing system that does not fully printan image on an edible article, or prints such image out of registration.In such case, the image may not be legible or only a part of the imagemay be visible, causing consumer disappointment.

In the past, when printing on edible substrate sheets, properlyregistering an image to an individual portion has been achieved bymechanically linking the printer and the cutter. For example, in U.S.Pat. No. 5,534,281, issued Jul. 9, 1996, and U.S. Pat. No. 5,162,119,issued Nov. 10, 1992, both to Pappas et al., it is disclosedregistration of images printed on a dough sheet such that a subsequentcutter separating a portion of a dough sheet will contain a printedimage and the cutter and image are in registration. In this method, thisis accomplished by mechanically linking the printer and the cutter as asingle unit, wherein the printer is a rotary type, such that onerevolution of the rotary printer roll corresponds to one revolution ofthe cutter roll. Disadvantages of such a unit include that the number ofimages that can be used is limited to those that can fit on the limitedsurface area of the printer roll as a function of the size of theprinter roll, thus limiting the variety of printed images that can besupplied to consumers. Furthermore, if a greater number of images aredesired, the roll would need to be changed with losses of productiontime to change the roll, etc. Also, the printer roll is required tocontact the dough sheet that can have negative sanitation implicationsthat are difficult to mitigate.

Accordingly, it would be desirable to provide a means to print images onan edible substrate sheet (e.g. dough sheet) whereby the number ofimages available for printing is not so limited and is not limited byconstraints of the equipment, and still achieve proper imageregistration with a subsequent unit operation such as an ediblesubstrate sheet cutter. Furthermore, it would be desirable to avoidcontact of the edible substrate sheet by the printing means to avoidnegative sanitation implications.

It would be, therefore, advantageous to devise methods to deliverprinted content consistently on edible substrates with properregistration on edible substrates. Furthermore, it would be advantageousto do so with printing devices that allow for flexibility of imagevariety.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides a method of making ediblesubstrates having consistent registration of images disposed thereon. Inone embodiment, the method comprises:

-   -   (a) providing an edible substrate sheet;    -   (b) providing an image source, wherein said image source        comprises at least one image;    -   (c) providing a trigger pulse signal, wherein said trigger pulse        signal relays the frequency of a process element;    -   (d) communicating the trigger pulse signal to an image disposal        device, wherein the image disposal device uses the trigger pulse        signal to determine when to dispose an image from said image        source;    -   (e) disposing an image on said edible substrate sheet with said        image disposal device to form an image-disposed edible substrate        sheet;    -   (f) separating at least a portion of said edible substrate sheet        to form at least one image-disposed edible substrate piece.

These and other features, aspects, and advantages of the presentinvention will become evident to those skilled in the art from readingof the present disclosure.

All documents cited herein are incorporated by reference in theirentirety. The citation of any document is not to be construed as anadmission that it is prior art with respect to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. Example of trigger pulse signal (1) with baseline (2) and fourpulses (3).

FIG. 2. Example of adjusted trigger pulse signal (11) with baseline (12)and four pulses (13), wherein, the pulses have been cleaned of noise,and adjusted for their magnitude and duration.

FIG. 3. Status signal (35) and trigger pulse signal (30) are combined insignal processing unit (39) to form an adjusted trigger pulse signal(40).

FIG. 4. Example of search pattern areas (50), (51) and (52).

FIG. 5. Example of reference image (55).

FIG. 6. Search pattern of FIG. 4 is overlaid on reference image of FIG.5 to determine if image being analyzed is a reference image.

FIG. 7. Spectral profile of an exemplary magenta ink (62) on a doughsheet and of the dough sheet base (61). The vertical axis representspercent of light reflected on the specific substrate at the variouslight wavelengths of the horizontal axis.

FIG. 8. Percent difference of the spectral profiles of FIG. 7 from thespectral profile of the substrate with the exemplary magenta ink.Highlighted box (65) indicates region of highest contrast.

FIG. 9. Exemplary cutter roll (71) with incorporated sensor (81).

FIG. 10. Exemplary sensor (82) location prior to cutter roll (72).

FIG. 11. Exemplary cutter support roll (78) with incorporated sensor(83).

FIG. 12. Exemplary cutter support roll (79) with incorporated sensor(84) and matching cutter roll (74) with incorporated light aid (85) toaid sensor (84).

FIG. 13. Dough sheet (91) print process (121) with camera sensor (85),cutter (75) and images printed in registration (101) with cut doughpieces (96).

FIG. 14. Dough sheet (91) print process (122) with camera sensor (85),cutter (75) and images (102) printed out of registration with cut doughpieces (96) and resulting into partial images (103) and (104).

FIG. 15. Process diagram to print images in registration

DETAILED DESCRIPTION OF THE INVENTION

Although the invention herein will generally be described in terms ofprinting on a dough sheet, it should be understood that any suitableedible substrate sheet and any suitable means of disposing an imagethereon is within the scope of the present invention.

Preferred image disposal devices for use herein are those that enablethe disposal of a large variety of images without a need to change apiece of equipment. For example, the images that can be printed are notlimited by the physical constraints of the equipment. One such imagedisposal device for use herein can include ink jet printers,particularly piezoelectric drop-on-demand printers. Such ink jetprinters can draw image information from an image source, such as adigital storage media, which can store as many images as desired.

However, using an ink jet printer, presents two specific problems.First, printing on a timely fashion to coincide with the cutting ofdough pieces downstream from the printer. Second, printing at a speedthat coincides with the speed of the dough sheet. Overcoming these twoproblems is not a problem of a printer roll as disclosed by Pappas etal., when the gears of the printer roll and cutter roll are mechanicallyconnected such that both rolls move simultaneously and are located nextto each other; however, when using ink jet printing, the synchronizationbetween the two gears is not part of the system. Thus, some other meansmust be used to synchronize the printing of images with the subsequentcutting of the dough sheet to result in individual dough pieces havingimages properly registered thereon. One skilled in the art wouldrecognize that such development could also be used to synchronize theprinting of images with other unit operations as well, like, forexample, seasoning application, spray application, embossing operation,or a secondary printing application.

a. Providing an Edible Substrate Sheet

According to the present invention, an edible substrate sheet isprovided. The edible substrate sheet can be in the form of a continuoussheet or stream comprised of edible material that is later divided intomany resulting individual pieces. In one embodiment, the ediblesubstrate sheet is a dough sheet.

As used herein, “sheet” can include a substrate that has been shaped,extruded or roll-milled in such a way as to provide a flattened surfaceon the substrate.

As used herein, “stream” means a continuous source of substrates. Forexample, a stream of substrates can include a plurality of substratessuch as that provided by a conveyor belt or as a feed from a continuous,semi-continuous, or batch process.

As used herein, “edible substrate” or “substrate” includes any materialsuitable for consumption that is capable of having an image disposedthereon. Any suitable edible substrate can be used with the inventionherein. Examples of suitable edible substrates can include, but are notlimited to, dough sheets. Furthermore, suitable edible substrates caninclude snack chips, fabricated snacks (e.g., fabricated chips such astortilla chips, potato chips, potato crisps), extruded snacks, cookies,cakes, chewing gum, candy, bread, fruit, dried fruit, beef jerky,crackers, pasta, sheets of meat, sheets of cheese, pancakes, waffles,dried fruit film, breakfast cereals, and toaster pastries.

In a preferred embodiment, the edible substrate comprises a dough sheetused to fabricate a fabricated snack piece, preferably a fabricatedsnack chip, and more preferably a fabricated potato crisp. Suitablesnack pieces include those described in “Chip Frying Machine,” U.S. Pat.No. 3,520,248, issued Jul. 14, 1970, to MacKendrick; “Preparation ofChip-type Products,” U.S. Pat. No. 3,576,647, issued Apr. 27, 1971, toLiepa; “Apparatus for Preparing Chip-Type Products,” U.S. Pat. No.3,608,474, issued Sep. 28, 1971, to Liepa; and “Molding Device forPreparing Chip-Type Products,” U.S. Pat. No. 3,626,466, issued Dec. 7,1971, to Liepa; Lodge in U.S. Pat. No. 5,464,643, and Villagran et al.in U.S. Pat. No. 6,066,353 and U.S. Pat. No. 5,464,642. In oneembodiment, the fabricated snack chip is a fabricated potato crisp, suchas that described by Lodge in U.S. Pat. No. 5,464,643, and Villagran etal. in U.S. Pat. No. 6,066,353 and U.S. Pat. No. 5,464,642. Other snackchips that can be used herein include those described in “Process forMaking a Corn Chip with Potato Chip Texture,” U.S. Pat. No. 4,645,679,issued Feb. 24, 1987 to Lee, III et al.

In addition, the edible substrate can include pet foods such as, but notlimited to, dog biscuits and dog treats.

The edible substrate can be in any suitable form. For example, thesubstrate can be a finished food product ready for consumption, a foodproduct that requires further preparation before consumption (e.g.,snack chip dough, dried pasta), or combinations thereof. Furthermore,the substrate can be rigid (e.g., fabricated snack chip) or non-rigid(e.g., dried fruit film). In one embodiment, the edible substrates areconnected to one another (e.g., in the form of a dough sheet prior tocutting the individual pieces).

As used herein, “fabricated snack piece” or “snack piece” is broadenough to include a snack piece that has not yet been separated (e.g.,cut) from a dough. For example, in one embodiment, an image is disposedupon a dough sheet, then the dough sheet is later cut into individualpieces. Furthermore, “fabricated snack piece” or “snack piece” is broadenough to include both cooked (e.g., fried) and un-cooked (e.g., dough)substrates.

b. Providing an Image Source, Wherein Said Image Source Comprises atLeast One Image

As used herein an “image source” includes any collection of one or moreimages. For example, the image source can be an electronic (e.g.,computer-based) database, a plurality of databases, or a collection ofhard-copy images.

Images can be in any suitable form, preferably electronic media such asthat generated using computer software and stored on an electronicstorage device, such as a computer, computer disk, RAM, or ROM, orvisual display. Any suitable computer system, as known in the art, canbe used.

Images from said image source can be used by the image disposal devicein any suitable sequence, such as a repeating sequence, at random, orany predetermined order.

Preferably, all the images in the image source are different from oneanother. However, in one embodiment, at least two of the images in animage source are the same.

Preferably, each image can be identified by an identifier, e.g., asequential number or letter, that allows the image to be selected fromthe image source. For example, in one embodiment, each image isidentified by a unique number (e.g., 100 images are each assigned adifferent number from 1 to 100). Assigning an identifier to each imageallows for, among other things, cataloging of images and selection ofimages from the source by identifier (e.g., by number or letter). Inanother embodiment, an identifier is assigned to a portion of a clusterof images.

Any suitable image can be used. The image can comprise one or moregraphic elements, one or more text elements, or combinations thereof. Asused herein, “text” means one or more alpha-numeric symbols. Text caninclude letters, numbers, words, and combinations thereof.

As used herein, “graphic” means pictorial representation. For instance,the graphic can include objects, symbols, scenes, people, animals, toys,or characters. Suitable characters can include cartoon characters andlicensed characters, as well as characters associated with popularpersonalities in the media, advertising, or well known in the particularculture.

Non-limiting examples of suitable images include letters, numbers,words, animals, cartoon characters, popular figures from the media,caricatures, historic events, and photographs.

Furthermore, images can be in the form of full or partial words,numbers, clues, hints, jokes, revelations, trivia quizzes, photographs,pictures, puzzles, stories, games, or sequence of events (e.g.animations). For example, the image can comprise the question portion ofa trivia quiz. In one embodiment, the image depicts a piece of a jig-sawpuzzle.

c. Providing a Trigger Pulse Signal, Wherein Said Trigger Pulse SignalRelays the Frequency of a Process Element

When printing multiple images, it is necessary to instruct the printerwhen to begin printing each image. One such way of providing thoseinstructions is via a trigger pulse signal. This trigger pulse signalcan include those points in time when printing needs to occur such thatthe image is printed in proper registration, such that upon cutting theedible substrate sheet into pieces, the images are located on the pieceson the target location. As used herein, “signal” means an impulse or afluctuating electric quantity, such as voltage, current, or electricfield strength, whose variations represent coded information. Forexample, a trigger pulse of the trigger pulse signal is a change in thevalue of that signal which can be detected by the system to trigger anaction (e.g., printing). Thus, a trigger pulse signal is a collection(e.g., sequence) of one or more trigger pulses distributed over a periodof time, which instructs the system when to print, as instructed by eachindividual trigger pulse.

A trigger pulse signal comprises at least one trigger pulse. As usedherein, a “trigger pulse” can trigger the system to dispose an image.

The trigger pulse signal is associated with the frequency of an elementof the process (“process element”) that is used to form or convey aparticular portion of the dough sheet in processing (e.g., a particularportion that will be separated after printing to form an individualpiece and that is desired to have a registered image printed thereon).For instance, when making a printed fabricated chip, the trigger pulsesignal can be associated with the frequency of cutters cutting, orfrequency of cooking molds receiving a dough piece. Any suitable processelement can be used herein; for instance, the process element can beselected from a group of devices used to form or convey that portion ofthe dough sheet corresponding to an individual edible substrate, such asa forming device, cutting device, cutter mold, carrier mold, cookingmold, or conveying device. FIG. 1 shows a trigger pulse signal (1)having a baseline (2) and trigger pulses (3). The signal value (SV) isindicated by the vertical axis, which changes over time (T) indicated bythe horizontal axis. Someone skilled in the art would realize that thetrigger pulses may be based on a frequency change as opposed to anamplitude change as shown on FIG. 1. Furthermore, the trigger pulses maybe based on an amplitude change (e.g., low amplitude to high amplitude).Furthermore, the trigger pulses may be based on a bit change fordata-based signals.

The trigger signal can be of any suitable type. For instance, thetrigger signal can be electrical, light, magnetic, or a combinationthereof.

In one embodiment, the trigger signal correlates to the frequency atwhich individual substrates are moving through the line (e.g., are beingconveyed through the line). The frequency can tell how many substratesare being conveyed per unit of time, and can remain constant (e.g., ifthe line speed is constant) or can change over time. This frequency isincorporated into the trigger pulse signal in the form of properlyspacing the trigger pulses. This proper spacing is accomplished bysynchronizing the generation of the trigger pulses to the processelement to create a trigger pulse signal. In one embodiment, thefrequency at which fabricated snack chips are produced matches thefrequency at which printing of individual images on the dough sheetoccurs.

The creation of a trigger pulse signal may lead, however, to a signalthat is not readily useable (e.g., readable) by a printing system. Thus,it may be necessary to adjust the signal such that it is usable by thesystem. Such adjustment can include, for example, insuring that eachtrigger pulse is of sufficient magnitude and duration to be detectableby the printer, or removing signal noise. Furthermore, even if thesignal is usable by the system, the signal may require adjustment suchthat the system prints the images in proper registration, as discussedbelow. FIG. 2 shows an adjusted trigger pulse signal (11) having abaseline (12) and trigger pulses (13). The signal value (SV) isindicated by the vertical axis, which changes over time (T) indicated bythe horizontal axis.

As used herein, “proper registration” means that an image is disposed onthe sheet such that the image is located on a predetermined location onthe individually separated substrate containing that image. Accordingly,the method herein can be used to achieve registration of images in areproducible manner over a plurality of separated edible substrates.

In a particular embodiment, the trigger pulses are generated by analgorithm that takes into account the speed of a process element andportions of that process element that are directly related to individualedible substrates. For example, knowing the rotational speed of a cutterroll and both the number and spacing of cutter molds on its periphery,trigger pulses can be generated that correspond to the frequency of flowof individual edible substrates.

Although the trigger pulse signal provides a frequency, it may notalways be desirable to use that frequency such that an image is printed.In a particular embodiment, a status signal is used to provideinformation relating to the condition of a portion of the system. Inanother embodiment, a status signal can communicate whether to print ornot print. This information can be used to determine if a particulartrigger pulse will be used for printing or not. As used herein, a“status signal” communicates information regarding the status of atleast a portion of the system. In one embodiment, multiple status signalsources can be used with the invention herein to provide information todetermine whether an image should be printed as a result of anyparticular trigger pulse. For instance, a particular combination ofstatus signals can be used to communicate that printing should occur. Inone embodiment, all status signals must communicate print readiness inorder for printing to occur. In another embodiment, a certaincombination of status signals must communicate print readiness in orderfor printing to occur.

d. Communicating the Trigger Pulse Signal to an Image Disposal Device,Wherein the Image Disposal Device Uses the Trigger Pulse Signal toDetermine When to Dispose an Image from Said Image Source

The trigger pulse signal and, optionally, the status signals, arecommunicated to a signal processing unit (e.g., computer) to form anadjusted trigger pulse signal. The adjusted trigger pulse signalcomprises a message understandable by the printer, that indicates to theprinter when to print and when not to print. Thus, the status signalcommunicates information that is used to decide whether to dispose animage or not (e.g. whether the disposal of an image should occur even ifit is indicated by the trigger pulse signal). FIG. 3 shows an example ofa trigger pulse signal (30) with sets of trigger pulses (31), (32) and(33) and a status signal (35) with portions (36), (37) and (38), asinputs to a signal processing unit (39), which processes signals (30)and (35) to create an adjusted trigger pulse signal (40) that maintainssets of trigger pulses (41) and (43) equivalent to the set of triggerpulses (31) and (33) of trigger pulse signal (30), but not maintainingtrigger pulses in time period (42) corresponding to the time period oftrigger pulses (32) as indicated by portion (37) of the status signal(35), being of a predetermined value different than the predeterminedvalue of portions (36) and (38) of the status signal (35).

In one embodiment, information is evaluated against set criteria todetermine whether during a certain point in time printing should beexecuted or not; if those criteria are satisfied, then printing occursas indicated by the relevant trigger pulses during said certain point intime.

The status signal can communicate a message about any suitable elementof interest to a particular system (e.g., if the mill is running, thendough is there). There can be multiple signal sources that communicatewhether a particular part of the system is enabled or disabled at aparticular point in time. For instance, a status signal can communicate,among other things, that a cutter is removed, dough is not present,dough is present, dough is torn, some defect in the dough, dough will bediscarded, or a stuck chip is in a frying mold (e.g., do not printbecause the portion of dough that would have gone into that frying moldwill be discarded).

The status signal can be in any suitable form. For instance, the statussignal can be electrical, magnetic, light, or a combination thereof.

In one embodiment, the status signal and trigger pulse signal arecommunicated to a signal processing unit (e.g., computer) to form anadjusted trigger pulse signal. As used herein, the “adjusted triggerpulse signal” results from a combination of the status signal and thetrigger pulse signal. In a particular embodiment, the trigger pulsesignal is communicated to a signal processing unit (e.g., computer) toform an adjusted trigger pulse signal. The adjusted trigger pulse signalis “readable” by the printing system, and communicates whether to printor not to print an image, or at what particular point to print it.

In one embodiment, the trigger pulse signal relays the frequency of aprocess element to a signal processing unit, where the trigger pulsesignal is processed and adjusted to incorporate 1) time delays, or 2)information (e.g., status signals). As used herein, a “time delay” is aform of calibration delay; the time delay ensures that the images are inproper registration. The time delay works in combination with theprinting frequency indicated by the trigger pulse signal to determinethe time at which an image is disposed, either before or after a triggerpulse is due to occur by a time magnitude equal to the time delay.

As used herein, a “delay” can be either positive (+) or negative (−).The delay can be adjusted in order to position the timing of printing.In one embodiment, the trigger pulse is used to keep images inregistration, but the system is first calibrated by either manuallymoving the print head or adjusting the delay. If the delay is positive(+), then printing is set to occur after the trigger pulse signal by atime magnitude equal to the delay or as a function of the delay value.If the delay is negative (−), then printing is desired to occur beforethe trigger pulse signal by a time magnitude equal to the delay or as afunction of the delay value. In this case, for example, a feedback loopcan be incorporated in the system to determine if an adjusted triggerpulse was ahead of the original trigger pulse by the proper time amountafter printing occurs, as a function of the negative (−) delay. Thismeasures performance of anticipating a trigger pulse after the fact, andcan result in more variability. It is preferred to use positive (+)delays.

In a particular embodiment, a calibration step is used to either adjustthe delay applied to each trigger pulse, or to adjust the location ofthe print head such that proper registration is achieved. For instance,a registration mark that is sensed by a sensor can be used (e.g.,registration mark is printed on the sheet next to where each piece willbe printed, or one every 100 images, etc.); if the system senses themark, then the system will print in registration. Otherwise, the timedelay must be adjusted to move subsequent registration marks back intothe pre-determined sensor area; the intervening time between is thedelay from then on forward in the process.

The time delay can be determined manually, such as by continuouslyadjusting the time delay and visually monitoring the location where theimages are printed in relation to the target location on the individualedible substrates. Once this calibration is done, the printer system canrely on the trigger pulse signal and the so determined time delay toprint at the appropriate points in time that result in individual ediblesubstrates with images registered in the target location.

Alternatively, the time delay can be determined automatically, such asby use of a registration mark. The registration mark could be an imageprinted for that purpose or it could be an image intended to be part ofthe finished product. Also, the image could be printed in an area of theedible substrate intended to become part of the finished product or not.In either case, such registration mark is detected by a sensor locatedin proximity to the unit that separates the edible substrate (e.g. acutter roll for a dough sheet), or further downstream in the process,such that a comparison can be made between were the registration mark isand where it should be in the individual edible substrate. The closerthe sensor is to the cutter, the more accurate the registration will be.When this comparison is made, the system can then determine or adjustthe time delay until the images are printed in proper registration. Forexample, FIG. 13 shows the use of registration marks (105). In thisexample, a printer (100) prints on a dough sheet (91) that will beeventually cut into dough pieces (96) by a cutter roll (75), to befurther transferred to frying molds for frying of the dough. One row ofdough pieces (96) are cut with a rotary cutter (75), and images (101)are printed on the dough sheet (91) for each of the eventually to be cutindividual dough pieces (96). Around each dough piece (96) is a web ofdough (92) that will be recycled and mixed with fresh dough. Aregistration mark (105) is printed every three images in the portion ofthe dough sheet (91) that will become the web (92). A sensor (85)detects the registration mark (105) near to where the dough pieces arecut.

The sensor could be located within the cutter roll. FIG. 9 shows anexample of a dough sheet (90) being cut into individual dough pieces(95), with a cutter roll (71) that comprises a sensor (81) within. Inthis example, the sensor (81) rotates as the cutter roll (71) rotates.The sensor (81) can be adjacent to or within a cutter mold in theperiphery of the cutter roll (71), and as the sensor (81) reaches thedough sheet (90) once per revolution, it detects the presence andlocation of an image such as a registration mark, in relation to thecutter mold, or the lack of an image.

Alternatively, the sensor could be located outside the cutter. FIG. 10shows an example of a dough sheet (90) being cut into individual doughpieces (95), with a cutter roll (72) and a sensor (82) located above thedough sheet (90) to detect images on the dough sheet prior to reachingthe cutter roll (72). FIG. 11 shows an example of a dough sheet (90)being cut into individual dough pieces (95), with a cutter roll (73),and a cutter support roll (78) that comprises a sensor (83) within. Inthis example, the sensor (83) rotates as the cutter support roll (78)rotates. The sensor (83) is located to coincide with a point on thecutter roll (73) near a mold of the cutter roll (73). As the sensor (83)reaches the dough sheet (90) once per revolution, it detects thepresence and location of an image such as a registration mark, inrelation to the cutter mold, or the lack of an image. If the image isprinted on the face of the dough that faces the surface of the rotarycutter (73), and this creates difficulties to the sensor (83) to detectimages (e.g., images are on the opposite side of the dough), then alight could be used from within the cutter roll to enhance the contrastof the printed mark against the surrounding not printed dough area. Asmany dough sheets are translucent, this approach can enable the sensorto better detect the registration mark. FIG. 12 shows an example ofthis, wherein the cutter roll (74) comprises a light source (85) and thecutter support roll (79) comprises the sensor (84) that matches up withthe light source once per revolution.

Alternatively, a time delay is not used, and, rather, the image disposaldevice is moved along the length of the dough sheet until properregistration of images on the individual dough pieces is achieved. Oncethis manual calibration is done, the printer system can rely on thetrigger pulse signal to print at the appropriate points in time thatresult in individual edible substrates with images registered in thetarget location. Alternatively, the distance between the image disposaldevice and the subsequent unit operation, like the cutter operation, isadjusted to accomplish the manual calibration. Furthermore,alternatively, the speed of the substrate may be adjusted independent ofthe subsequent unit operation to accomplish the manual calibration.

Just as the image disposal device can be moved along the length of thedough sheet to calibrate the registration, we must note that the reverseinadvertent change of the distance (or time) between the image disposaldevice and the subsequent unit operation, like a cutting operation, canresult in loss of registration. For example, a sudden air entrapmentunderneath the dough sheet that was not there earlier, in a locationbetween the image disposal device and the cutting operation, may resultin change of the distance that the dough sheet may travel between theimage disposal device and the cutting operation, resulting in a loss ofregistration. Note that air entrapment is not necessarily what causesthe loss of registration, but rather the change in the amount of airentrapment. In general, means will be used to maintain constant thedistance between the image disposal device and subsequent unitoperation, like cutting. Methods to control the potential variation inthe said distance as a result of changes in the amount of airentrapment, can include, but are not limited to, use of rollers orforced air over the dough sheet to keep it pressed against the conveyorbelt, or use of vacuum under the conveyor belt to remove such air.

In one embodiment, a signal is generated from the cutter unit, transferroll, or other key system area, and processed to form an adjustedprinter trigger pulse. Adjusting the signal in this manner to form anadjusted signal pulse provides a signal the printer can read, as well asallows for the incorporation of status signals.

In one embodiment, an image to be printed with an ink jet printercomprises rows and columns of dots each of which is intended to compriseink or to be left blank. Columns extend along the length of the doughsheet in the direction of dough sheet movement. Rows are at an angleversus the columns. In one particular case, the rows are perpendicularto the columns with an angle of 90 degrees. The distance between columnsas printed on the dough sheet is a function of how the ink jet printeris positioned over the dough sheet and how far apart the ink jet nozzlesare from one another in the print head. The distance between rows asprinted on the dough sheet is a function of how fast the dough sheet ismoving and how fast the ink jet printer is instructed to printconsecutive rows. If the dough sheet is made to move faster and thespeed of printing consecutive rows is not changed, then an image willappear stretched. To avoid this, the speed at which the dough sheetmoves is measured and a jetting frequency is communicated to the imagedisposal device to correspond with the speed of the dough sheet. In oneembodiment, the jetting frequency is communicated to the image disposaldevice by a jetting frequency signal that, similar to the trigger pulsesignal, comprises a trigger pulse for each row of dots to be printed.The jetting frequency signal can be created automatically (e.g., asensor determines the speed of the dough sheet which is thencommunicated appropriately to the image disposal device) or manually(e.g., with a rheostat).

In one embodiment, the jetting frequency is created automatically withthe aid of an encoder unit. An encoder unit produces a signal withtrigger pulses as a function of the rotation speed of the encoder unitshaft and the characteristics of the specific encoder unit. For example,some encoder units are designed to produce one trigger pulse perrevolution of the encoder shaft, while others are designed to produce afinite number of trigger pulses per revolution of the encoder shaft(e.g., 500 trigger pulses per revolution). In a particular embodiment, awheel is connected directly to the encoder shaft, and the wheel islocated above the dough sheet, which is made to move with the motion ofthe dough sheet. As the wheel motion makes the encoder shaft move aswell, a signal can be generated from the encoder unit. In an alternateembodiment, the wheel is connected indirectly to the encoder shaft via aset of mechanical gears to scale the rotation speed of the shaft to aspecific speed as a function of the speed of the dough sheet. In oneembodiment, the signal produced by the encoder unit is the jettingfrequency signal. In another embodiment, the signal produced by theencoder unit is used to create the jetting frequency signal.

In one embodiment, an encoder measures the speed at which a dough sheetis moving indirectly (e.g. by measuring the speed of the dough sheetbelt conveyor). In one embodiment, the dough sheet speed is convertedthrough an algorithm to a jetting frequency signal (e.g., number of KHzor thousands of ink droplets printed per second by an ink jet nozzle),which determines how quickly the image disposal device prints. Inanother embodiment, a rheostat can be used to adjust the jettingfrequency of the image disposal device.

In one embodiment, an encoder measures the speed at which a dough sheetis moving, and this speed is used in conjunction with the distancebetween the image disposal device and the subsequent unit operation,like cutting, to determine an automatic adjustment to the previouslydetermined time delay. The previously determined time delay is specificfor a given substrate speed, and as the substrate speed changes, it maybe necessary to adjust the time delay. If the dough sheet speeddecreases, then it will take a longer time for a printed image that hasjust been disposed on the dough sheet to reach the cutter, and the extratime it takes to get there represents that less time delay is needed fora given trigger pulse signal to print in registration with a subsequentcutter operation. Analogously, if the speed of the dough sheet isincreased, then it will take a shorter time for a printed image that hasjust been disposed on the dough sheet to reach the cutter, and thelesser time it takes to get there represents that additional time delayis needed for a given trigger pulse signal to print in registration witha subsequent cutter operation. Someone skilled in the art should be ableto calculate the adjustment for the time delay, given the initial andnew dough sheet speeds, and the distance from printer to cutter.

e. Disposing an Image on Said Edible Substrate Sheet with Said ImageDisposal Device to Form an Image-disposed Edible Substrate Sheet

The trigger pulse signal, or the adjusted trigger pulse signal, is thencommunicated to an image disposal device. The computer uses the triggerpulse signal (or adjusted trigger pulse signal) to determine when tobegin to dispose an image from the image source. The trigger pulsetriggers disposal of an image to at least a portion of the substratesheet to form image-disposed edible substrate sheet. Alternatively, thetrigger pulse can communicate that an image should not be disposed.

The trigger pulse communicates to the image disposal device to disposean image on the substrate sheet to form image-disposed ediblesubstrates. As used herein, an “image-disposed edible substrate” is anedible substrate having an image disposed thereon. The disposed imagecan cover part or all of the visual portion of the edible substrate. Inaddition, the image can include one or more text or graphics disposedupon said edible substrate.

As used herein, “disposed on” means that one element can be integralwith another element, or that one element can be a separate structurebonded to or placed on another element. Thus, the image can be applieddirectly or indirectly to the edible substrate, applied to a materialthat is placed on the edible substrate, applied within the ediblesubstrate, or other variations or combinations thereof. In particularembodiments, the image can be printed, sprayed, or otherwise applieddirectly on the surface of the substrate. In other embodiments, theimage can be applied to a material placed on the surface of thesubstrate.

Any suitable means of disposing an image on the substrate can be usedherein. For example, the image can be printed, drawn, painted, orotherwise attached to the edible substrate. The image can besingle-color or multi-color. The image can comprise dyes, pigments,other natural or synthetic substances, flavors or combinations thereof.

For instance, in one embodiment, an ink jet printer is used to disposethe images. For example, a piezoelectric drop-on-demand ink jet printercan be used with the present invention herein.

The image can be disposed on the edible substrate before or after acooking process (e.g., before or after a dough sheet is baked or fried).Furthermore, the image can be disposed on the edible substrate before orafter it is cut into individual pieces (e.g., before or after a doughsheet is cut into individual cookie or snack chip pieces).

In one embodiment, the image is printed on the substrate. Methods ofprinting can include, but are not limited to, laser and ink jet (e.g.,thermal bubble jet, piezoelectric drop-on-demand, continuous ink jet).

In another embodiment, an edible sticker comprising an image is affixedto the substrate.

In another embodiment, a thin film comprising an image is affixed to thesubstrate via edible adhesive.

In a preferred embodiment, an ink jet image is printed on a fabricatedsnack chip.

In one embodiment, more than one surface of the edible substrate has animage disposed thereon. For example, a plurality of image disposaldevices can be employed, each one to dispose an image on different sidesof the edible substrate (e.g., top, bottom, and/or side)

In one embodiment, the image disposal device comprises a printer.Preferably, digital printing is used, such as ink-jet printing systems(e.g., continuous jet, drop-on-demand), such as those described in WO01/94116 by Willcocks et al., published Dec. 13, 2001. In a preferredembodiment, an inkjet printer disposes images on a dough sheet, which iscut into individual pieces then fried to form fabricated snack chips.

f. Separating the Edible Substrate Sheet into Individual Pieces

In one embodiment, the adjusted trigger pulse signal enables the cuttingmechanism to coincide with a portion of the edible substrate comprisingan image. The trigger mechanism enables the location of the image suchthat the cutter coincides. In this example, the cutter is passive andthe printer via the trigger pulse signal is active. By “passive,” it ismeant that the cutter does not seek to cut in a specific locationcoinciding with an image location; by “active,” it is meant that theprinter, via the trigger pulse signal (or adjusted trigger pulsesignal), anticipates when to print an image such that the image is inproper registration with the subsequent cutting.

Any suitable cutter can be used. For instance, rotary or stamp cutterscan be used.

In one embodiment, the adjusted trigger pulse signal enables the cuttingmechanism to coincide with that of the image location. Because theprinting system used herein is “active,” this allows the individualpieces cut from the edible substrate sheet to be cut in such a mannerthat each image is registered properly on the corresponding individualpiece. Thus, the use of a “passive” cutter, which cuts at the same placeon the sheet as it comes through, can be used herein for makingindividual pieces with registered images.

g. Alternate Embodiments of the Invention

In another aspect, the present invention provides a method forconsistent image registration, wherein the stream of edible substratesis conveyed by a conveyor belt, comprising:

-   -   (a) a stream of edible substrates;    -   (b) a conveyor belt to convey said stream of edible substrates;    -   (c) an image disposal device located in proximity to said stream        of edible substrates;

wherein the image disposal device is in closer proximity to a highertension portion of the conveyor belt than to a lower tension portion ofthe conveyor belt.

Preferably, the printing occurs on a portion of the conveyor belt thatis higher than the median tension, at least in near proximity to thehigh tension zone.

In one embodiment, the highest tension (“high tension zone”) of the beltis that portion which is greater than the median tension of the belt. Inanother embodiment, the highest tension of the belt is the top portionof the belt, wherein the belt has two shafts. In a particularembodiment, the high tension zone is past the drive shaft, in themachine direction, or the portion of the conveyor belt that is beingpulled by the drive shaft. In another embodiment, the high tension zoneis the area of the entire belt, wherein said belt has the same tensionthroughout, preferably wherein said belt is made of metal. Conveyorbelts tend to experience a more consistent movement next to the driveshaft pulling them, where the belt is in high tension, maintaining aspeed that is closely aligned to the tangential speed of the driveshaft. Locating an image disposal device in closer proximity to the hightension zone, makes use of the improved speed consistency and enablesimproved registration of images. Lower tension zones tend to accommodatebelt slack and this can result in speed upsets from one moment to thenext that are less desirable for printing in registration.

In a particular embodiment, the method for consistent image registrationcomprises:

-   -   (a) a stream of an edible substrates;    -   (b) a conveyor belt to convey said stream of edible substrates,        wherein said conveyor belt comprises a drive shaft; and    -   (c) an image disposal device;        wherein the image is disposed on a portion of the stream of        edible substrate that is located between 0 and 30 feet (0 and        9.1 meters) of the closest drive shaft for the conveyor belt.        Preferably the image is disposed on a portion of the stream of        edible substrate that is located between 0 and 20 feet (0 and        6.1 meters) of the closest drive shaft for the conveyor belt,        more preferably 0 and 10 feet (0 and 3 meters), yet more        preferably 0 and 5 feet (0 and 1.5 meters) and most preferably 0        and 2 ft (0 and 0.6 meters).

Alternatively, the dough sheet is held more firmly to the conveyor beltto minimize slipping of the dough sheet on the conveyor belt that cannegatively affect image registration. This can be achieved by vacuumholding the sheet down on the conveyor belt from under the belt or byusing pinch rollers that would hold the sheet from both top and bottomsides while turning to assist the sheet forward movement.

An alternative use of the trigger pulse signal described comprises usingit as a comparison element against a second signal that records pulsescorresponding to when individual images have been printed or laterdetected on edible substrates. In this embodiment, the pulses from thetrigger pulse signal are not used to trigger printing of images, butrather, they are compared with the pulses of the second signal in timeto determine if a pulse from the trigger pulse signal has acorresponding pulse in the second signal, and also that pulses from thesecond signal occur at the same frequency within a time period as pulsesin the trigger pulse signal. If the frequency of occurrence of pulses inthe second signal does not match the frequency of pulses in the triggerpulse signal, then this event can be used to increase or decrease theprinting frequency until the frequency of occurrence of pulses in thesecond signal matches the frequency of occurrence of pulses in thetrigger pulse signal. Also, once the frequencies match, if acorresponding pulse in the second signal does not occur simultaneouslyor within certain time tolerance of a given pulse in the trigger pulsesignal, then this can be used as an indication that the calibration timedelay needs to be adjusted in proportion to the time difference betweenthe occurrence of the given pulse and the corresponding pulse in thesecond signal to ensure proper registration of images takes place.

h. Image Quality Control

In another aspect of the invention, a camera is used to capturephotographs of the printed images on the edible substrate for qualitycontrol. The captured photographs are then analyzed by an operator or bya computer for a number of attributes. A strobe light is used inconjunction with the camera to photograph the desired image disposed ona moving edible sheet. The strobe light illuminates the edible substrate(e.g, printed dough sheet) very briefly to capture the instant when theprinted image passes by the camera. The contrast between the areas ofthe edible substrate containing ink versus that of areas not containingink can be analyzed.

A filter passing light in a specific portion of the wavelength spectrumcould be used to further improve the contrast between areas of theedible substrate containing ink and areas that do not contain ink. Thespecifications for a given filter can be determined by comparing thespectral profile of the edible substrate with ink and the ediblesubstrate base without ink. The spectral profile of a material shows thepercent of light reflectance off the surface of the material (% R) overthe spectrum of light wavelength. FIG. 7 shows exemplary spectralprofiles for a non-printed dough sheet (61) and for the same dough sheetwith magenta ink on it (62). FIG. 8 shows that the difference betweenboth spectra expressed as a percentage (% D) of the magenta ink spectrumindicates a region of maximum difference between the two spectralprofiles between about 500 nanometers (nm) and 560 nm, highlighted bybox (65). In this particular example, a filter passing light between 500nm and 560 nm would reduce overall image brightness but would providefor better contrast detection between ink and substrate. Such filtercould be used to filter the light reflected off the edible substratebefore it reaches the camera. Alternatively, the filter could be used tofilter the light of the strobe light before it reaches the ediblesubstrate to be reflected.

The camera and the strobe light are triggered off the same trigger pulsesignal used to trigger the image disposal device. A time delay from thepoint that the image disposal device prints is used to trigger thecamera and strobe light as a function of how far downstream the cameraand strobe light are located, and how fast the edible substrate ismoving.

When the camera captures a photograph of the edible substrate, thephotograph can be analyzed to determine if it contains the correspondingimage disposed by the image disposal device, if it is positionedproperly, and if other potential problems exist. The analysis focuses oncontrast areas found on the captured photograph. From the found contrastareas, a true center of the image can be calculated and compared to anexpected center location that will deliver registered images on theindividual edible substrates upon being cut with a cutter. Deviations ofthe calculated true center from the expected center indicate problems ofpositioning. Also, a boundary can be set within which a photograph isexpected to contain contrast areas. If contrast is seen outside of thedesignated boundaries, then this could indicate poor positioning ofimages on the edible substrate or other contamination of the ediblesubstrate. If, however, no contrast areas are found when they areexpected, this could indicate an equipment failure.

A specific image, known as a reference image, can be used to conductmore detailed analysis. The reference image is designed with specificfeatures that the camera will analyze. Such reference image may bedetectable by the vision system for further analysis, or the visionsystem is made to expect it ahead of time for further analysis.Preferably the vision system is able to recognize the reference image sothat additional analysis can be triggered. In one embodiment thefrequency of more detailed analysis is determined by the frequency ofdisposing the reference image. The more detailed analysis may include,for example, tests for the performance of individual nozzles of a printhead. Also, failure by the vision system to find the reference image onan expected frequency can indicate various failures of either printingsystem or vision system capability.

Detection of the reference image can occur by detection of at least onespecific design element of the reference image. For example, a designelement comprises a vertical line extending across the whole image thatcan be found by the vision system. In another example, the referenceimage design comprises a specific pattern of ink density that can bedetected by the vision system (e.g. ink in all four corners of the imageand none in the middle). FIG. 4 shows an example of a search pattern fora vision system wherein boxes (51) designate areas where a high inkdensity is expected and (52) designate areas where a low ink density isexpected. If a photograph meets these criteria, then that indicates thatthe photograph contains a picture of a reference image that could beanalyzed further. FIG. 5 shows an example of a reference image withareas of high ink density (56), and FIG. 6 shows the same referenceimage of FIG. 5 with the search pattern of FIG. 4 overlapped, that showshow the reference image meets the exemplary predetermined criteria,wherein areas (57) have high ink density corresponding to the searchareas (5 1) of the search pattern (50) and also corresponding to theareas of high ink density (56) of reference image (55), and areas (59)have low or none ink density corresponding to the search areas (52) ofthe search pattern (50).

Testing for the performance of individual nozzles of a print head is animportant aspect of producing high quality images. If a portion of thenozzles used to dispose an image malfunction (e.g. become plugged), thenparts of the intended image will not be disposed. This can lead to imagedefects. The severity of the defect increases with increasing number ofmalfunctioning nozzles (e.g., 90 malfunctioning nozzles out of 256nozzles is more severe than 20 out of 256 nozzles), or if themalfunctioning nozzles concentrate in an area of the print head width(e.g., if there is several malfunctioning nozzles consecutive or near toone another). A reference image can incorporate a region of specific inkdensity that have been printed by a number of ink jet nozzles.Preferably each ink jet nozzle contributes equally towards the inkdensity of the image. If the sensor detects that the measured inkdensity is lower than expected, it could indicate one or more jetnozzles malfunctioning. In one embodiment the number of ink jet nozzlesmalfunctioning is proportional to how much lower ink density is measuredin the region versus what is expected when all ink jet nozzles arejetting properly.

EXAMPLE

The present invention is demonstrated by the following non-limitingexample.

Example 1

FIG. 15 shows an overview of an exemplary set up for practicing thepresent invention. A dough sheet 90 is conveyed towards a rotary cutter(72) with a stationary axis to for form individual dough pieces (95). Itis desired to dispose images from the image source (160) on the doughsheet (90) with an ink jet print head (100) that are registered with thesubsequent cutting performed by the cutter roll (72), and to result inimage disposed dough pieces (95). A trigger pulse signal (154) iscreated from the cutter roll (72) that comprises the frequency of cuttermolds of the cutter roll (72) cutting the dough sheet (90) in the formof trigger pulses distributed over time, wherein each trigger pulsecorresponds to a cut performed by the cutter roll (72). The triggerpulse signal (154) is input to the signal processing unit (170) thatprocesses said signal to produce adjusted trigger pulse signals (157)and (158) while considering exemplary status signals (151), (152), and(153), a manually input calibration time delay (155), and optionally anencoder signal (159). The adjusted trigger pulse signal (157) is used bythe ink jet printer (100) to determine when to begin disposing of eachimage. The adjusted trigger pulse signal (158) is used by the camerasystem (82) to determine when to capture pictures of the dough sheet(90) to correspond with instances when the images are in line of sightof the camera sensor (82). An encoder (130) generates a jettingfrequency signal (156) and (159) based on the measured speed of thedough sheet (90) by a wheel connected to the encoder shaft that moves asthe dough sheet (90) moves. The jetting frequency (156) is communicatedto the ink jet printer (100) so it prints all corresponding rows of dotsof an image at a speed that corresponds appropriately with the speed ofthe dough sheet (90) to deliver a consistent image length from image toimage. The optional jetting frequency (159) can be communicated to thesignal processing unit (170) to provide for automatic adjusting of theprovided time delay signal (155), as a function of a potential speedchange of substrate (90) as measured by the encoder (130), and also as afunction of the distance between the ink jet print head (100) and thepoint where the cutter roll (72) separates a portion of the substrate(90) to form image disposed dough pieces (95).

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

1. A method of making edible substrates having consistent registration of images disposed thereon, wherein said method comprises: (a) providing an edible substrate sheet having at least one image disposed thereon; (b) providing a trigger pulse signal, wherein said trigger pulse signal relays the frequency of a process element; (c) communicating the trigger pulse signal to a piezoelectric drop-on-demand ink jet printer, wherein the piezoelectric drop-on-demand ink jet printer uses the trigger pulse signal to determine when to record an image to said edible substrate sheet; (d) communicating a recorded image to an image analyzer, wherein said image analyzer determines whether the edible substrate image meets predetermined criteria; and (e) disposing the recorded image on said edible substrate sheet with said piezoelectric drop-on-demand ink jet printer wherein the edible substrate image meets said predetermined criteria; wherein said edible substrate sheet is a fabricated snack dough sheet wherein said fabricated snack dough sheet comprises a material selected from the group consisting of potato, rice, corn, wheat, and combinations thereof; wherein a camera having a filter lens to increase the contrast between the printed image and the edible substrate sheet is used with a strobe light to produce the recorded image; and wherein said camera and said strobe light are triggered off the same trigger pulse signal used to trigger said printer.
 2. The method of claim 1, wherein said image analyzer determines whether the actual location of a printed image corresponds with the target location for said printed image.
 3. The method of claim 2, wherein the piezoelectric drop-on-demand ink jet printer is located before a cutter unit and the target location is analyzed in relation to the cutter.
 4. The method of claim 2, wherein the ink jet printer is located after a cutter unit and the target location is analyzed in relation to the outline of the cut piece. 